氧化鱼油通过调控AMPK影响黄鳝脂肪分解代谢的研究

In recent years, oxidized fish oil diets are used in aquaculture feed, which leads to excessive lipid deposition in liver or abdominal cavity. This seriously affects the growth and health of the aqual animal. Excessive lipid deposition in liver is a sign of abnormal lipid metabolism. The mechanism of oxidized fish oil on lipid deposition process and regulation is very obscure in fish. Ricefield eel, Monopterus albus Zuiew, is an economically important fresh fish species in China. Feeding experiment and hepatocyte cell model with combined molecular biological techniques will be used in this research. Effects of different oxidized fish oil levels on expression of key genes in lipolysis as well as AMPK signaling pathway will be evaluated. Furthermore, on basis of hepatocyte cell model, studies will be conducted to further investigate how AMPK and signaling pathways to affect lipolysis in fish. In conclusion, the regulation mechanism of oxidized fish oil on lipolysis with affecting AMPK signaling pathways is expected to be elucidated based on the project, and be as the theoretical basis of solving the problem of abnormal lipid deposition.

氧化油脂饲料的使用，导致养殖鱼类肝脏或腹腔中脂肪过度沉积，严重影响了鱼类生长和健康。脂肪过多沉积是脂肪代谢异常的表象。目前，氧化鱼油影响水产动物机体脂肪代谢机理尚不明确。本项目以我国重要淡水经济鱼类黄鳝为研究对象，通过摄食生长实验和离体肝细胞模型，系统探讨饲料氧化鱼油对鱼体脂肪分解代谢关键酶基因表达的影响，探明氧化鱼油通过影响AMPK信号通路进而对分解代谢的调控作用，构建AMPK在鱼类上影响机体脂肪分解代谢的信号通路。通过上述研究，拟探明氧化鱼油对鱼体脂肪分解代谢影响机理及其调控机制，为解决脂肪异常沉积问题提供理论基础。

油脂对脂肪代谢和鱼体生长具有重要意义。油脂中的不饱和脂肪酸易被氧化、酸败，同时氧化、酸败的产物如过氧化物、丙二醛等对鱼类具有毒副作用，并进一步影响了鱼体的健康和品质，给养殖业造成巨大损失。黄鳝养殖过程中最重要的疾病是肝胆综合症。该项目以我国重要的淡水特色经济鱼类黄鳝为对象，比较研究了高氧化鱼油水平以及苹果多酚和牛磺酸的添加对黄鳝生长、抗氧化和脂肪分解代谢的影响。通过本项目的研究得到如下结果：高氧化鱼油日粮并未影响黄鳝的生长和饲料利用；氧化油脂在黄鳝肝脏和肌肉中均可通过AMPK影响黄鳝脂肪分解代谢，主要通过AMPK-ACC-CPT1和AMPK-lipin-PPARα-CPT1途径；氧化鱼油日粮会刺激黄鳝肝脏体内糖异生代谢加强；高氧化鱼油组肝脏细胞明显变性，出现较多脂肪空泡；肠道结构不完整，杯状细胞数量骤减，出现大量空泡。高氧化鱼油组黄鳝丙二醛含量显著升高；氧化鱼油日粮会诱导肠道菌群失衡，增加菌群涉及碳水化合物、能量、多糖合成和代谢的基因的丰度，特别是有关脂多糖的合成代谢的基因，由此可能会引起肠道炎症反应。在氧化鱼油日粮中添加0.5%苹果多酚或0.2%牛磺酸对黄鳝肝细胞和肠道组织结构均有一定的改善作用，且添加0.2%牛磺酸可促进黄鳝肠道菌群平衡并恢复其功能到与对照组相当水平。氧化鱼油日粮中添加0.5%苹果多酚或0.2%牛磺酸对黄鳝生长、饲料利用以及AMPK引导的信号通路均有改善作用。该研究结果为AMPK介导的脂肪分解代谢研究奠定了重要的理论基础。